Seq

Sequential strategies provide ways to compositionally specify the degree of evaluation of a data type between the extremes of no evaluation and full evaluation. Sequential strategies may be viewed as complimentary to the parallel ones (see module Control.Parallel.Strategies).

General purpose finite sequences. Apart from being finite and having strict operations, sequences also differ from lists in supporting a wider variety of operations efficiently.
An amortized running time is given for each operation, with n referring to the length of the sequence and i being the integral index used by some operations. These bounds hold even in a persistent (shared) setting.
The implementation uses 2-3 finger trees annotated with sizes, as described in section 4.2 of
* Ralf Hinze and Ross Paterson, "Finger trees: a simple general-purpose data structure", Journal of Functional Programming 16:2 (2006) pp 197-217. http://www.soi.city.ac.uk/~ross/papers/FingerTree.htmlNote: Many of these operations have the same names as similar operations on lists in the Prelude. The ambiguity may be resolved using either qualification or the hiding clause.